A coepokation oe washing



Nov 29, 1927. Re. 16,805

F. G. SIMPSON RADIO TELEGRAEH AND TELEPHQNE RECEIVING SYSTEM ATTORNEY Nov. 29, 1927. Re. 16,805

F. G. SIMPSON RADIO TELEGRAPH lAND TELEPHONE RECEIVING SYSTEM y 2 Sheets-Sheet 2 Orlginal Filed Nov. 4, 1922 A INVENTOR FZ7' 4 L ff'eaf//a'v fai 'mpso/z zag/MMM ATTORNEY Reuma Nev. 29, 1927.

UNITED STAT-Es PATENT OFFICE.

NIBEDEBICK GEANT SIMPSON, or SEATTLE, WASHINGTON, ASSIGNOR To SIMPSON nAnIo CORPORATION, or' SEATTLE, WASHINGTON, A CORPORATION OP WASHING- TON.

riginll llo. 1,507,889, dated September 9, 1924, Serial No. 598,976, led November 4, 1922. Application for RADIO TELEGRAPH AND TELEPHONE RECEIVING SYSTEM.

reissue illed September 7, 1926. Serial No. 134,116.

This invention relates to improvements in the arrangement and connections of electrical.

apparatus at the receiving stat-ion of a radio communication Stein; the object being to detect, andv amp ify the effect of received electro-magnetic waves and to reproduce the signals carried byl or the modulations 1n, such electro-magnetic Waves by means of similar variations in the electricall current in a circuitor 4in thediferences of electrical otentialbetween parts of such circuit, which is supplied by a local battery or other gentioned... "To this end I improved upon erator of electrical current in a manner to make them more perceptible andintelligible. The linvention also embodies an improved method of accomplishin the results menave modified and reviously known arrangements" of receiving circuits in a manner which will be clearly understood from -the following description in connection with the accompanying drawings.

It is to be noted that I have included in my improved arrangement of circuits certain known circuits and combinations of electrical apparatus, in an elementary way, to the extent that there is comprised therein, together with other known elementary circuits, a circuit having as an essentialv part, two three electrode electron tubes commonly known as audions, trio-des, etc., (ory their equivalent one five electrode electron tube) which circuit hasbeen described by W. H. Eccles and F. W. Jordan in British Patents 148,582 and 149,018, dated February 16, 192.0. It also embodies an inductance and capacitance,

in parallel, connected in series with the local enerator of` electric current, which has been s own by E. H. Armstrong, in United States 'Patent 1,113,149 of Oct. 6, 1914. I depart, however, from the customary use of all these known circuits by combining them together, adjusting their constants and associating them.with other electrical apparatus in a niannerwhich produces enormous amplifica- `tion .in the effect of the received electromagnetie'waves upon the current, or electrilcal potentials, supplied By the'local generator, thereb' causing the signalscarried by,

or theme ulations'n, such electromagnetic waves to be reproduced in greatly amplified form by a telephone receiver, or other cur- Militr.: s. 1

rent or potential actuated device, as will be understood from the following description.

In this description vI shall designate as triodes, three electrode electron tubes each embodying an evacuated vessel containing a hot cathode, an anode in the form of a plate or concentric cylinder and another electrode placed in a position, with respect to the cathode and anode, such that variations in itselectrical potential with respect to either of theother two velectrodes will cause like variations in the electrical current between them. I shall designate the anode of each triode as the plate; the cathode as the filament and the third electrode as the grida i l l In the drawings Figure 1 illustrates, diagrammatically,a simple form of my arrangement of the receiving circuit and electrical apparatus at a vradio communication station. Figure 2 represents a similar arrangement with the addition of a transformer for t'he passage of audio frequency currents and the impressing of audio frequency potentials between the grid and filament of one of the triodes. Figure 3 shows an arrangement like that of Figure 2 except that I have provided a third triode and have connected the secondary terminals of the audio frequency transformer to its grid and filament. I have also (if) v removed the telephone receiver, or other former being connected to the grid and filament of the third triode as shown in Figure 3.

`Like reference numerals designatelike parts throughout the several views.

Referring 'particularly to. Fig. 1,l 1` represents vthe ordinary elevated part of an antenne, at a radioreceiving station,j'which is electrically connected inseries in the order given, with a variable condenser 2, the switch 3, inductance coil 4, switch 5, inductance coil 6, to the ground or counterpoise 8; a variable ioo ' .manner to make them perceptible or intellicondenser 7'is connected in parallel with the active part of the inductance co1l 6 and provides alternative `branch` of the Aantenna circuit between the"V switch -and ythe ground 8. The switches 3 and 5 are preferably mechanically actuated by a control member commonto *bothv of them and so adjusted that the active partl of each of the coils 4 and 6 shall be of equal inductance. A variable condenser 9 is electrically connected in Series between the switch 3 and the grid 15 of a triode 13. A variable condenser 10 is electrically connected in series between thm und, lor counterpoise 8 and the grid 15 oglio triode .17 The plate 14 of the triode 13 vis electrically connected -to the ground, vor counterpoise 8. 11 represents a telephone receiver, or other current or potential actu- .ated device capablefof reproducing variations in the force which aotuates it in a gilde. In the following description I shall -refer to 11 as the telephone although it Yshould be understood Vthat this designation embraces any device of the kind mentioned. ,The telephone'll iselctrically connected in sgriesbetween .theswi'tch 3 and -thepla-te 14 .of the triode 17. Avariable condenser 12 is connected in parallel with the telephone l1 thereby providing ya path for radio frequence current from the switch 3 to the plate 14 of triode 17. The filament -16 of triode 13 has one of .its terminals electrically connected to the negative terminal of a battory, or other source of electrical current, 20; its other terminal is connected through a switch 18 and a current controlling rheostat `19 to the positive'terrninal of battery 20. The filament 16 of the triode 17 has one of its :terminals electrially connected to the negative terminal of the battery 20; its other terminal is connected through a switch 35 and a current controllingy rheostat 34 to the positive terminal. oef the battery 20. Another battery, .for other Vsource yof electric current 22,- has-its negative 'terminal electrically connected to the negative terminal 0f the Vbattery 20. fAn inductance coil 23 is electrically connected in series, between the positive terminal of the battery 22 and the switch V5. A oondenser21 is connected'in parallel with the ybattery 22. A variable condenser 24 is connectedin parallel with the induotance coil'23. Condensers 21 and 214A lprovide a -path for radio frequency currentsfrom the switch 5 to the filament y16, --offtriodp 13, andk ,tothe filament 16, of' the coil 4,

triode 1 .1.; shall hereinafter reier. tto the circuit which consists of the aerial antenna vstrucv,the...amidemser .2, switehf inductenee 55 `indu'ctance coil 6 `and een- Zjin parallel, 1and ground or :counterpoise as/the oscillatory circuit. This .to the same end. For all kinds identical and if vequal to each other.

.divided into Ytwo princi ry circuit vconstitutes .a vwell' .known temperaturel of the' filaments at a value,

largely established by the structural parameters of the triodes, suitable for .the'best operation of the-telephone 11, and dependent upon the kind of signal o1' current modula- ,tion involved in such operation. The voltage of the battery 22 should also be adjusted or modulations in the received electromagvnetic waves, the oscillatory circuit should be Vso adjusted, b means of the variable condensers 2 and il, or by means of the switches 3 and 5, as to be resonant at the frequenc of the received waves. The adjustment o the condensers 9, 10 and 12^is not critical if the adjustments of filament temperature, voltage ofrbattery 22 and condenser'24 are properly made. I have found it possible to substitute fixed condensers of approximately 0.001 micro-farads capacitance for the variable condensers 9, 10 and 12 shown in the drawings. The Vadjustment 'of the condenser 24 is dependent upon the kind of signal `received as will lbe 'hereinafter explained. The capacitance of the fixed condenser 21 vmay be established within acomparatively Wide range; I have found va value of 0.5 micro-farads .tofbe entirely satisfactory 'for all usual purposes. Vhile the inductance of thevcoil 23 may also be established at any value within Va Wide range I have been able to secure entirely satisfactory resultswith a coil havingan inducta'nce value of 14 millihenrys, direct current resistance of 10 ohms .and v'negligible capacitance, when connected, asshown by the drawing, in parallel with a varlable condenser 24 having la maximum capacitance of 0.005 lmicro-farads.

"If the rtriodes'13 and 17 `are structurally their'filaments have the same temperature the active parts of the coils 4 and having the .fame resistance, and the capacltance of condensers 9 and 10 being a current will be established from the positive terminalof the batter-y 22, which current may be considered as alcomponents, both existing in the coil v23 ut separating at the switch 5. Thelarger of these currents, finds a circuit from the switch 6to plateY1-4, of triode 13, thence rby means of the electronic conductivity ofthe triode, to its -lilament 16, and to minal of the battery 22. The` smaller current finds its circuit from. the yswitch 5. through the coil 4,v switch 3 and -telephone 11, to the plate 14, of triode 1,7 thence,by

of signalsy the negative ter- 5 through the coil l 10` tnodes of, the coil 23, switch and coi 6 upon to the the filament of such triode.

means of the electronic conductivity of suoli triode to its filament 16 and to the negative terminal of the battery 22. That this is the smaller. of the two principal current components is due to the added resistance of the telephone 11 in its circuit. It will be seen ...from the drawings and the previous description thereof, that an electricalv poten- `tial, positive to that of the filaments of the is impressed by the batte 22 by that conductor of condenser which is connected to the ground, or counterpoise, 8; there is therefore by means of the electrostatic induction of condenser 10, a potential negative with res ect to the filaments of the triodes, impresse upon the grid of the triode 17. In a like manner a positive p0- tential is impressed by the battery 22, by Way of the coil 23, coil 4, and switch 3, upon that conductor of condenser 9 which is connected to switch 3; there is therefore by means of the electro-static induction of condenser 9 a potential, negative with respect filaments of the triodes, impressed upon the grid 15 of the triode 13. In general these negative grid potentials will be unequal, due to the unequal distribution of current between the coils 4 and 6 and the consequent unequal drop in electrical potential between `the switch 5` and the terminals of these coils which are adjacent to condensers ligand 10 respectively. It is well known that un increase of negative potential, with respect to the filament, of a triode elfects a decrease in the current between the plate and In the present instance the negative potential of the grid 15, ofthe triode 17, is somewhat less, with nos ct to the filaments of the triodes, than i 'y ist at of the grid 15 of the triode 13. This isdue `to the fact that there is a larger curand consequently` a greater drop in lpotentiel in the coil '6 than there is in the c9514, t rough which coils the potentials upon the-grids of `triodea 17 and 13 are raspectivelyiimpressed. `It may readily be seen thutfrthis unequality in the grid potentials of the triodes tendsto decrease the current between the plate and filament of triode 131t0 a greater extent than is the case with `respectto the decrease in the current between the plate and filament of the triode 17 The read'ustment of current values between the coil s 4 and 6 tending to equality and between thetriodes 13 and 17 produces electrical oscillations in the oscillatory circuit due to the well known inherent proporties of circuits of its kind. An oscillating potential of opposite phase is therefore simultaneously impressed upon the grid 15 ofthe triodes 13 and 17, respectively causing the triodes to function as electrical valves alternately permitting'the establishment of "l entrent between their respective plates and to a description of the manner in which sustained oscillations are createdin the oscillatory circuit due to an initial unequal dis` tribution vof the current vbetween the coils 4 and 6 caused by the added resistance of the telephone 11 in the circuit which includes the plate of the triode 17 It is obvious that any one of many other causes of unequal distribution of current between these coils will have a similar effect, as for `example if the filament temperatures are not-properly ad justed, as described, or if ozcillationsv are generated in the oscillatory circuit by the introduction of an electromagnetic field, as is thecase at a radio receiving station during the passage of electromagnetic waves.

oscillations will be indenitely sustained In the oscillatory circuit as hereinabove described, their amplitudes being limited by t-he saturation characteristics of the triodes, unless the const-ants of the oscillatory cir cuit as so modified bythe introduction of resistance for example, as to increase the energy losses in that circuit to a greater quantity than the energy supplied by the battery 22. Sustained oscillations may also be preventedby reduction of the filamenttemperatures of the triodes to a value where the impedance of the triodes between their plates and filaments is suiiiciently large to limit the energy supplied-by the battery' 22, in the form of pulsating current, to a quantity less than losses of'energy in the oscillatory circuit.`

An additional means of veither suppressing, or controlling the duration of, oscillations in the oscillatory circuit, is provided by the variable condenser 24as shown on the drawing and hereinabove described.4

Thcfcircuit which consists of the condenser 24 and the inductance coil 23 has impressed upon it. between the common terminals of the condenser 24 and the indue-tance coil 23, an alternating component of electromotive.- force, supplied by the battery 22 and its associated circuits, which together with the direct electromotive-force, also supplied by the battery 22, produces in effect, a pulsa-ting current in that part of my arrangement of circuits which consists of the battery 22, inductance coil 23 and condenser 24 in parallel, and the electrical connection to the switch 5. It is Well known ythat if the circuit which consists of the inductance coil 23 and the that necessary to supply the110 condenser' 24 -isadjustedto be resonant at the` frequency of this alternating component vof electro-motive-forcefthat it will offer maximum impedance to currents of such frequency. In the present instance, I control the duration` of-oscillations in the oscillatory circuit including inductances 4 and 6 or suppress-them, either by adjusting the filament temperatures of the triodes,or, by adjusting the variable condenser 24. y

When maximum reinforcement of the oscillations, in the oscillatory circuit, is required, irrespeetive as to Whether such oscillations are to be sustained or not, it is necessary to adjust thev constants of the entire circuit whicli supplies current pulsations from the battery 22 to the switch 5, in a manner which will cause this circuit to be resonant at aA frequency which is twice that of the frequency of the oscillations in the oscillatory circuit. This may be readily understood yby considering the fact that unidirectionalcurrent pulsations must proceed from the switch 5, at each half cycle of an oscillation in the oscillatory circuit, to the oscillatory circuit, in phase with the current pulsation existing at the moment in either coil 4 or coil 6. In other words, each of these uni-directional current vimpulses must reach its amplitude at that `instant of time when each of the triodes, 13 and 17, offers minimum impedance between plates 14 and {ilaments 16 as4 governed by the potentials of grids 15 with respect to filaments 16.

When receiving signals, carried by groups of electromagnetic Waves, each group consisting of trains of such waves emanating from either a spark of interrupted continuous wave telegraph transmitting station; or when receiving telephone modulations in a. continuous stream of waves, I prefer to adjust 'the filament temperature of the triodes 13 and 17 at va value slightly lower than that' necessary to permit sustained oscillations the'oscillatory circuit; after which I .ad-

just the variable condenser24 so that the entire circuit .supplying 'energy from the 1ocircuit supplying energy from the battery cal battery 22 shall be resonant at twice lthe frequency of the current generated in the oscillatory circuit by the incoming electromagnetic waves. en receiving. signals carried by a continuous stream of waves emanating from a telegraph l transmitting station, I prefer to adjust the filamentY tem-` perature of the triodes at a value which will permit the existence of sustained oscillations in tlieoscillator'y circuit; after which I adjust the variable condenser 24 so that the entire 22` shall be resonant at a frequency either slightly more 'or less rthan twice the frequency of the .current generated in the oscillatory circuit by the incoming waves. lIn this case Vthe combined effect of two frequencies upon the current in the telephone ll proapparatus. In the other cases mentioned signals are reproduced in the telephone 11, by

the audio frequency interruptions in the continuity of, or audio frequency modulations in the `amplitude or length of, the incoming electromagnetic waves, through the medium ofthe currents generated by them in the oscillatory circuit and'` the indirect effect of such currents upon conductivity of the triodes, as is well known. In each of the cases mentioned it is to be understood that the oscillatory circuit is adjusted to be resonant at the frequency of the incoming waves, i

in the manner hereinabove described.

Referring to-Figure 2,-11 represents a telephone, shunted by the variable condenser 12, and connected in series between the ground, or counterpoise, 8, and the plate 14, of the triode 13. 27 represents the iron core of an audio frequency transformer, having a primary coil 26, shunted by the variable condenser 25, connected in seiies between the switch?) and Aplate 14, of triode 17, and a secondary coil 28, the terminals of which are connected to the grid l15 and the filament 16, respectively, of the triode 13. I have found it to be entirely satisfactory to substitute a fixed condenser having a capacitance of approximately 0.001 micro-farads of condenser 25 is to afford a path for radio frequency pulsations to the plate 14 of triode 17. Condenser. 12'affordsa path for radio frequency pulsations to the `plate 14,-of triode 1??. Audio frequency potentials, corresponding to the audio frequencies of the signals, beats, or modulations involved are impressed upon'tlie grid and filament of triode 1S by means ofthe inductive association of primary coil 26 with secondary coil 28, thereby superimposing" audio frequency variations in the potentialof the grid with respect to the filament of :triode 13. These variations in electrical potential produce like variations in the-currentbetween the plate 14 and the filament 16, of triode 13, and therefore in the current in thev telephone 11, greatly amplifying the effect of the received signals, or modulations, upon ythe telephone. In other respects the arrangement shown in vFig. 2 is 'the same as that shown by, and de- In Fig. 3 the plate 14 of triode 13 is con- 110 lthe lpositive terminal of battery 20.

slliectirely,` of4 a third triode 29, having a p ate 14. The telephone 11, shunted by the condenser `12, is connected in series between the `plate 1.4, of t'hetriode 29, and the positivefterminal of the battery One termi-4 nal ot' the filament 16, of triode 29, is connected to the negative terminal of battery 20. The other terminal Aof vthe filament 16, of triode 29,I is connected `by means of switch T-and current controlling rheostat l36, to The arrangement shown in Fig. 3 .functions in every respect the same as that shown in Fig. l-except that the audio frequency pulsations in the form of potential variations are conveyed by means of the primary and secondary coils 26 and 28 to the grid and filament of a third, or amplifying triode 29, thereby producing like variations in the current be#` tween the plate and filament of the amplitying triode,and there-fore in the current in the'telephone 11. This method of `audio frequency amplification is well known in the manner of its application to other systems, of radio reception. i

In Fig. v4 the secondary coil 28 has its terminals connected to the `grid and filament of the triode 13, as is the case in Fig. 2. en. audio frequency transformer, having an lron core 32, has its primary coil 31, shunted `bythe variable condenser 30, connected in series between-.the ground or counter-poise 8,

and the plate 14 of triode 13, the terminals ofthe secondary coil 33 are connected to the 15, and filament 16, respectively, of the triode 29, which is otherwise connected to, andtassociated with, the other parts of this arrangement of circuits, the same as has been shown, ,and described in connection with Fig. 3. The variable condenser 30 may be replaced by a fixed condenser of approximately 0.001 micro-farads capacitance. Audio frequency pulsations of great amplitude are present in the current in the pri mary coil 31 for the same reason as that explained in connection with the current in the telephone 11 as shown in Fig. 2. These audio frequency current pulsations are conveyed lin the form of potential variations, by the vsecondary coil 33 to the grid and filament of the triode 29, and are therefore reproduced, 1n still greater amplified form, in thecurrentin the telephone 11.

While I have shown various forms and kinds of apparatus as included in `the elementary parts of my arrangement of circuits, I do not desire to be limited, orv re*- stricted, in the broad scope of my inven- "tion,- as defined in the claims, to any specific 'structure of apparatus or its arrangement in elementary circuits, the assemblage of which forms the means of accomplishing the purposes hereinabove stated in substantially the manner herein described. It is obvious that many moditications, or changes, in the shape,

kind and arrangement of the various parts may be made without departing from the broad scope of the appended claims. 'As an example, it is clear that the action herein described may be obtained byv substituting one electron tube having a single ilament,

4at sources other than that described herein.

Having set forthfthe object and nature of my invention, and various means and arrangements of` accomplishing the purpose thereof, whatv I claim asnew and useful,4 and of my own invention, and desire'to secure by LettersPatent, is

1. Radio receiving apparatus embodying an oscillatory antenna circuit, an electric current generator, circuitmeans connecting said generator with said oscillatory antenna circuit, twoelectric Valves interposed in said circuit means and arranged to permit said generator to supply uni-directional current impulses to said oscillatory antenna circuit, the circuit including said generator being adjusted to be resonant at substantially twice the frequency of said .oscillatory antenna circuit- 2. Radio receiving apparatus embodying an'oscillatory circuit adjusted to be resonant at the frequency of incoming electromagnetic waves, a generator of electric current, circuit means connecting said generatorwith said oscillatory circuit, two elect-ric valves interposed in the circuit including said generator and arranged to be operated by the electric potentials generated in said oscillatory cirtric valves arranged to be operated by the electric potentialsy generated in said oscillatory circuit in a manner to permit said generator of electric current `to supply unidirectional current impulses to said oscillatory circuit, said uni-directional current impulses comprising dlrecty and alternating current components,-sa1d alternating current` l rent generator"` te supply current impulses' to said oscillating antenna circuit, which consists in part in adjusting the circuitl includi stantia ly twice-the kfrequencyof the oscil- '20 latcnyy antenna circuit.

5. Radio, receiving apparatus embodying.

an oscillatory circuit adjusted to be resonant at the frequency ofincoming electromagnetic waves, an electricv current generator,

.25 circuit means connecting said generatorwth said oscillatory circuit, two electric valves interposed in the circuit; including said gencrater and arranged to permit said generator to: supply current impulses to said oscillatory circuit, and meansincluding inductance.A and capacitance, in parallel, connected in' seriesbetween ,said electric current generaton andvsaid oscillatory circuit for adjusting. the circuit including said f generator tobe resonant at twicethe frequency of said oscillatory circuit.

6. Radio receiving apparatus. embodying .anoscillatory circuit yadjusted to be resonant at the frequency. of .incoming electromagnetic; 40 wares, two three electrode electron tubesA each having their anode and their third electrode .connected with said oscillatory circuit, anA electric current generator connected with the cathod of .said electrone tubes and with said oscillatory circuit and means for adjusting the circuit including said generator to be resonant;I at twice the frequency of said oscillatory circuit.

7J Radio receiving apparatus embodying 59 an oscillatory circuit adjusted to be resonant at the frequency of incoming electromagnetic waves, two electric triodes each having their imode-and grid connected with said oscillatory circuit, condensers interposed in rsaid-grid connections, a tele honeA receiver I interposed-.in one ofsaid ano e connections, Vari-:electric current/generator interposed between said- .oscillatory circuit and theA cathodas .of said triodes, and means for adjusting 69* the frequency. of the circuit including said generator to be resonant. at twice the frequenc of.A said'oscillatory circuit.

8. t a radio receiving station, an oscillatory circuit adjusted to be resonant at the frequency of incoming. electromagnetic said generator to be resonant at subwaves; a generator of electric currentconnected to, and associated with, said oscillatory circuit by means including two electric valves arranged to bel operated by the elecrtric potentials generated in Said oscillatory ponents, said alternating current component having twice the frequency of the resonant current in said oscillatory circuit; means for adjusting the circuit comprising said generator of electric current, and its connectionsV to, and with, said oscillatory circuit, to be resonant at the frequency of said alternating current'` component; and means for impressing electric potentials gcnerated by. variations in the current in one of the said electric valves upon the actuating members. of' theV otherV one of said elect-ric valves.AV y n 9. Radio receiving. apparatus embodying an oscillatory circuit adjusted to be resonant at the frequencyof vincoming electromagnetic Waves, a. generator of electric current, circuitmeans connecting said generator with said oscillatory circuit, two electric valves interposed in the circuit including said generator andarranged to'permitfsaid generator to supply uni-directional current impulses to said oscillatory circuit, the circuit including said generator being adjustedto be resonant at twice the frequency of said oscillatorycircuit and means for impressing electric potentials generatedby variations in the` current in one of said electric valves upon the actuatingmembers of the other of said electric valves.

10. Radio receiving apparatus embodying an oscillatory circuit adjusted to be resonant at the frequency of incoming electromagnetic waves, an electric current generator connected to and associated with, said oscillatory circuit, two electric valves interposed in the circuit including said generator and arranged to be operated by the electric potentials generated in said oscillatory circuit. to permitfsaid generator to supply uni-directionalcurrent impulses to said oscillatory circuit, said current impulses coniprising direct and alternating current comfponents,rsaid alternating current component havingtwice the frequency of the resonant current in said oscillatory circuit, means including inductanceand capacitance, in parallel, connected in series between said electric current generatorv and said oscillatory circuit for adjusting the circuit includingsaid generator to be resonant at the frequency of said alternating current component and a transformer connected With said electric valves for impressing electric potentials generated by variations in the current one of said electric valves upon the actnatmg members of the other of said electric valves` j 11.,"Atl a lradio receiving station, an oscillatry circuit adjusted to be resonant at the frequency of incoming waves, a generator of electric current, connected to, and associated with said oscillatory circuit by vmeans includin two electric j valves arranged to be operate by the electric potentials generated in said oscillatory circult in a manner to permit said generator of electric current to supply uni-directional usaid uni-directional current impulses comprising direct and alternating current com- Onents, Said alternating current component liavigg twice the frequency of the resonant current in said oscillatory circuit; means for adjusting the circuit comprising said generato'r of electriccurrent, and its connecy tionsltopand with, said oscillatory circuit, y i; tobe resonant at the frequency of said alternatingcurrent component; a third electric valve arranged to control the current in a separate circuit, supplied by said generator of electric current, and arranged to be operated by electric potentials generated by variations 1n the current in one of aforesaid r, electric valves; and means for impressing said electric potentials upon the actuating vmembers of said third electric valve.

12.. Radio receiving apparatus embodying an loscillatory circuit adjusted to be resonant at the frequency of incoming electromagnctic waves, a generator of electric current; cir'uit means connecting said generator and said oscillatory circuit, two electric valves interposed `in the circuit including said gencrater and `its connections with saidoscillatory circuit and arrangedv to .permit said enerator to supply uni-directional current impulses to said oscillatory circuit, the circult including said generator being adjusted to beresonant at twice the frequency of said oscillatory circuit, a third electric valve arranged to be operated by electric potentials of said first named electric valvesl and to `control the current in a separate circuit supplied by said generator and lneans for impressing said electric potentials upon the actuating members of said third electric valve.

13. Radio receiving apparatus embodying an oscillatory circuit adjusted to be resonant at the frequency of incoming electromagnetic waves, a generator of electric current, circuit means connecting said generator and said oscillatory circuit, two' electric valves interposed in the circuit including said generator and its connections with said oscillatory circuit and arranged to permit said generator to supply luni-directional current impulses to said oscillatory circuit, the circuit including said generator being electromagneticr current impulses to said oscillatory circuit, j

ers interposed in each of said third electrode generated by variations in the current in one adjusted to be resonant at twice the frequency of said oscillatorycircuit, another circuit connected withsaid generator, a third electric valve interposed in said other circuit and arranged-to be operated `by elec- T tric potentials, generated by variations in the current in ono vof said first named electric valves, means for impressing said electric potentials upon the actuating members of said third electric valve and means for translating variations of electrical energy in Said other circuit into sound. i

14. Radio receiving apparatus embodying an oscillatory circuit adjusted to be resonant at the frequency of incoming electro- 5U magnetic waves, a generator of electric current; circuit means connecting said generator and said oscillatory circuit, two electric` yalves interposed in the circuit including vsaid generator and its connections with said S5 oscillatory circuit and arranged to permit said generator to supply uni-directional current vimpulses `to said oscillatory circuit, the circuit including said generator being adjusted to be resonant at twice the frequency of said oscillatory circuit, means for impressing electric potentials generated by variatons in the current in one of said electric valves upon the actuating members of the other of said electric valves, another circuit connected with said generator, a third electric valve interposed in said other circuit and arranged to be operated byv electric potentials generated by variations in the current in one of said first named electric l valves and means for impressing said electric potentials upon the actuating members of said third electric valve.

15. Radio receiving apparatus embodying an oscillatoryvcircuit adjusted to be resonant l at the frequency of incoming electromagnetic waves, two electric triode valves each having their anode and their third electrode connectcd with said oscillatory circuit, condensl lll connections, transformers each having their primary coils interposed in the respective' connections to said two anodes, the secondary coil of one of said transformers being connected to the third electrode and the l cathode of one of said electric triode valves, an electric current generator connected with said oscillatory circuit and the cathodes of said electric valves, inductance and capacitance in parallel connected in series between said generator and said oscillatory circuit, a third electric triode valve having its third electrode and cathode connected with th-e secondary coil of the other transformer, and a telephone receiver connected between said lfgenerator and the anode of said third electric valve.

16. The method of amplifying an alternating electric current which consists in reinforcing each half cycleof such alternating lilo electrically connected together at one end in substantially non-inductive relation to each other and having a capacity element interposed between them lat the other end, land control means for admitting dir-ect current impulses from said source separately through the respective inductance elements at alternate moments of time and in phase with an oscillation current fiowing in the oscillatory circuit. y A

19. An oscillation system comprising a source of direct current, a`n`oscillatory circuit having a pair of inductance elements connected together at one end in substantial- 1y non-inductive relation to cach other and having a capacity element interposed between them at theother end, a. connection from the positivev pole of said source Vof direct current to said inductance elements at the end at which they are connected together, and control means for admitting direct current impulses fromv said source separately through the respective inductance elements' at alternate moments of time but always in the same direction and in phase with an loscillation current flowing in the oscillatory circuit.

20. An oscillation system comprising a source of direct current, an oscillatory cirphase with the oscuit having ai pair ofk inductancev ele-ments electrically connected together at one end in substantially non-inductive relation to eachother and having a capacity element interposed between them at the other end, and means actuated by an oscillation current in said oscillation circuit for admitting direct current impulses from said source separately through the respective inductance elements at alternate moments of time but alvvaysin the same direction and in phase with the oscillation current.

21. An oscillation system comprising in combination a source of direct Current, an oscillatory circuit having a pair of inductance elements electrically connected together at one end in substantially non-inductive relation to each other and having a capacity element interposed between 'them' at the other i Yendl and control means for admitting direct current impulses from said source through one of'said inductance elements at recurrent moments of tim-c but always in the same diA rection and in phase with an oscillation current flowing in the oscillatory circuit.

22. An oscillation system comprising in combination a source of direct current, an oscillatory circuit having a pair of inductance elements electrically connected together at one end in substantially non-inductive re-` lation to each other and having a capacity elem-ent interposed between them at the other vend, a triode tube having its cathode circuit connected to the negative pole of said direct current source, a connection from the positive pol-cof said direct current source to the said inductance elements at the end at which they are connected together, a connection from the opposite end of one of said inductance ele-ments to the anode of said triode tube, and a capacity connection from the opposite end of the other of said inductance elements to the grid electrode of said triode tube.

' FREDERICK GRANT SIMPSON. 

